Create OmniboxMetricsProvider class.

chrome/browser/metrics/omnibox_metrics_provider.h

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_METRICS_OMNIBOX_METRICS_PROVIDER_H_
+#define CHROME_BROWSER_METRICS_OMNIBOX_METRICS_PROVIDER_H_
+
+#include "base/basictypes.h"
+#include "components/metrics/metrics_provider.h"
+#include "components/metrics/proto/chrome_user_metrics_extension.pb.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
+
+struct OmniboxLog;
+
+// OmniboxMetricsProvider is responsible for filling out the |omnibox_event|
+// section of the UMA proto.
+class OmniboxMetricsProvider : public metrics::MetricsProvider,
+                               public content::NotificationObserver {
+ public:
+  OmniboxMetricsProvider();
+  virtual ~OmniboxMetricsProvider();
+
+  // metrics::MetricsDataProvider:
+  virtual void OnRecordingEnabled() OVERRIDE;
+  virtual void OnRecordingDisabled() OVERRIDE;
+  virtual void ProvideGeneralMetrics(
+      metrics::ChromeUserMetricsExtension* uma_proto) OVERRIDE;
+
+ private:
+  // content::NotificationObserver
+  virtual void Observe(int type,
+                       const content::NotificationSource& source,
+                       const content::NotificationDetails& details) OVERRIDE;
+
+  // Records the input text, available choices, and selected entry when the
+  // user uses the Omnibox to open a URL.
+  void RecordOmniboxOpenedURL(const OmniboxLog& log);
+
+  // Registar for receiving Omnibox event notifications.
+  content::NotificationRegistrar registrar_;
+
+  // Saved cache of generated Omnibox event protos, to be copied into the UMA
+  // proto when ProvideGeneralMetrics() is called.
+  metrics::ChromeUserMetricsExtension omnibox_events_cache;

[Ilya Sherman, 2014/05/20 15:26:49]

Can we use just the ominbox portion of the protobuf?

[Alexei Svitkine (slow), 2014/05/20 15:49:26]

It's a repeated field, so not easily. (Unless we actually use the internal proto
RepeatedType collection...)

+
+  DISALLOW_COPY_AND_ASSIGN(OmniboxMetricsProvider);
+};
+
+#endif  // CHROME_BROWSER_METRICS_OMNIBOX_METRICS_PROVIDER_H_